This invention relates to ratchet wrenches, and more particularly to open-end ratchet wrenches that can be placed on a workpiece from the side.
There are many occasions when it is desirable to apply torque to a workpiece (such as nuts, bolts, and in-line hydraulic fittings) in order to, for example, rotate the workpiece with respect to a threaded member. Two well known tools for rotating workpieces are ratchet wrenches and open-end crescent wrenches. Ratchet wrenches are typically close-ended devices that completely encircle the workpiece and are thus installed on the workpiece from the top (or bottom, depending upon the orientation of the workpiece). By contrast, open-end wrenches can be installed from the side of the workpiece.
Open-end wrenches are particularly useful in small spaces where there may only be sufficient room to install the wrench from the side. Moreover, in confined spaces, there is often insufficient space to accommodate the ratchet mechanism of typical close-ended ratchet wrenches. In addition, open-end wrenches are a must for tightening/loosening in-line fittings of hydraulic or fuel lines, which can only receive a wrench from the side.
Typical open-end crescent wrenches lack a ratchet mechanism. As a result, during a tightening or loosening operation, the wrench must be removed from the workpiece after it has rotated the workpiece a relatively small amount (such as 30 degrees), and then replaced thereon at a different angle for continued rotation. This procedure is repeated (often many times) until the workpiece is completely tightened or loosened.
Open-end ratchet wrenches that resemble typical crescent wrenches have been developed for confined and in-line fitting applications. Some open-end ratchet wrenches employ numerous spring-loaded rollers, cams, or pawls for engaging the workpiece; others use an insert shaped to fit over the workpiece and engage an internal ratchet mechanism. Some of these wrenches encircle the workpiece to such an extent that, even though the wrenches have open ends, they must actually be installed vertically from above or below the workpiece.
Another open-end ratchet wrench, described in my U.S. Pat. No. 5,456,143, includes a pair of elongated plates that are pivotally mounted to a pair of spaced jaws on the wrench handle. A spring mounted on the handle engages the plates and biases them toward each other so that the plates grasp and turn the workpiece when the handle is rotated in a driving direction. The spring bias is overcome when the handle is turned in the opposite direction, allowing both plates to pivot on the jaws and slide over the faces of the workpiece in a ratcheting manner.